Human leukocyte antigen blood transfusion

Contamination of blood products with lymphocytes can lead to transfusion-induced reactions ranging from a mild fever to severe reactions such as alloimmunization and graft versus host disease (GvHD), in which the transfused lymphocytes (graft) survive the defensive immune reaction of the patient (host) and start a reaction which destroys the cells of the host. The patient also may develop an immune response to the human leukocyte antigen (HLA) type of the graft s cells and reject all platelet transfusions that do not match their own HLA system. The HLA system, found on blood platelets and lymphocytes, is more compHcated than, but similar to, the ABO blood group system of red cells. 

Transfusion-induced autoimmune disease has been a significant complication in the treatment of patients who require multiple platelet transfusions. Platelets and lymphocytes carry their own blood group system, ie, the human leukocyte antigen (HLA) system, and it can be difficult to find an HLA matched donor. A mismatched platelet transfusion does not induce immediate adverse reactions, but may cause the patient to become refractory to the HLA type of the transfused platelets. The next time platelets with an HLA type similar to that of the transfused platelets are transfused, they are rejected by the patient and thus have no clinical efficacy. Exposure to platelets originating from different donors is minimized by the use of apheresis platelets. One transfusable dose (unit) of apheresis platelets contains 3-5 x 10 platelets. An equal dose of platelets from whole blood donation requires platelets from six to eight units of whole blood. Furthermore, platelets can be donated every 10 days, versus 10 weeks for whole blood donations. 

Besides obtaining blood samples to address trauma, obtain blood samples for complete blood counts helpful in estimating exposure dose, paying particular attention to the lymphocyte count and human leukocyte antigen typing before any initial transfusion. 

Leukocyte-depleted blood products, particularly red blood cell concentrates, are clinically used to avoid negative side effects in recipients after transfusion. Possible leukocyte-associated post-transfusion complications include human leukocyte antigen alloimmunization, graft-versus-host disease, platelet refractoriness, and transmission of viruses. Amongst the various existing techniques for the selective removal of leukocytes from blood, filtration has become a popular method, because of its convenience and lowcosts. Leukocyte filters have been specially developed for the purpose they generally consist of fibrous materials made of Nylon, PAN, cotton wool, cellulose acetate,or polyester. Currendy available filters... 

---